Grasses in Your Pocket: A Guide to the Prairie Grasses of the Upper Midwest (Bur Oak Guide) [1 ed.] 1609382382, 9781609382384

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A BUR OAK GUIDE

GRASSES

IN YOUR POCKET

A Guide to the Prairie Grasses of the Upper Midwest

Anna B. Gardner, Michael Hurst, Deborah Lewis, and Lynn G. Clark

FLOWERING HEADS BRANCHED Branches More or Less Dense  ➔ Junegrass, prairie junegrass Koeleria macrantha see also panel below Native. May–Aug. Frequent. Dry prairies, grassy woods, sandy soils. 20–130 cm, 0.5–4.5 ft high. Clumping; leaves relatively short & basal. IA, IL, IN, MI, MN, OH, WI

Slender wedgegrass

➔

Sphenopholis intermedia

Prairie wedgegrass

Northern reedgrass

➔

Sphenopholis obtusata

➔

Native. May–Aug. Frequent. Moist to wet prairies, clay soils. 5–120 cm, 0.5–4 ft high. Flowering heads nodding, branches loose; spikelets hairless. IA, IL, IN, MI, MN, OH, WI

Calamagrostis stricta subsp. inexpansa

Native. Jun–Aug. Widespread but infrequent. Moist low areas, marshes, dunes, forests, disturbed sites. 9–130 cm, 0.5–4.5 ft high. Flowering heads erect, branches dense; spikelets hairless. IA, IL, IN, MI, MN, OH, WI

Native. Jun–Aug. Infrequent with localized distributions. Prairie marshes. 10–120 cm, 0.5–4 ft high. Spikelets hairy at base. IA, IL, IN, MI, MN, OH, WI

 ➔ Composite dropseed, rough dropseed Sporobolus compositus see also panel below Native. Aug–Oct. More common south. Dry prairies, roadsides, cedar glades, partially disturbed semiopen sites. 40–130 cm, 1–4.5 ft high. Spikelets 4–6 mm long, rounded at tip. IA, IL, IN, (MI), (MN), OH, (WI)

Phalaris arundinacea Exotic. May–Sep. Common, often aggressive. Wet prairies; fields; edges of lakes, ponds, ditches, & creeks. 40–230 cm, 1–7.5 ft high. Rhizomes scaly; ligule a well-developed membrane 4–10 mm long. IA, IL, IN, MI, MN, OH, WI

Calamovilfa longifolia Native. Jul–Sep. Infrequent. Loess bluffs, sandy soils. 50–240 cm, 1.5–8 ft high. Spikelets hairy at base. IA, IL, IN, MI, MN, (OH), WI

Little bluestem

➔

➔

Marsh muhly

Sand reedgrass, prairie sandreed

➔

Reed canarygrass

➔

FLOWERING HEADS BRANCHED Branches More or Less Dense

Muhlenbergia racemosa

Schizachyrium scoparium

Native. Jul–Oct. Occasional to frequent west of IN. Dry prairies, rocky slopes, sandstone outcrops, wet meadows, edges of fields & roads. 30–110 cm, 1–4 ft high. Flowering heads erect & rigid, branches dense. IA, IL, (IN), (MI), MN, WI

see also panel at right Native. Mid Jul–Oct. Common. Dry prairies. 30–210 cm, 1–7 ft high. Reddish stems with whitish blue waxy bloom; flowering heads hairy; awns 2.5–17 mm long. IA, IL, IN, MI, MN, OH, WI

 ➔ Plains muhly Muhlenbergia cuspidata Native. Late Jul–Sep. Rare east of IL. Dry gravelly prairies, limestone outcrops, sandy soils. 20–60 cm, 0.5–2 ft high. Crown knotty; leaves narrow; flowering heads not hairy; spikelets unawned. IA, IL, (IN), (MI), MN, (OH), WI

see also panel at left Native. Mid Jul–Oct. Common. Dry prairies. 30–210 cm, 1–7 ft high. Reddish stems with whitish blue waxy bloom; flowering heads hairy; awns 2.5–17 mm long. IA, IL, IN, MI, MN, OH, WI

Povertygrass

Sporobolus vaginiflorus Native. Aug–Oct. Frequent. Cedar glades, dry disturbed areas. 15–60 cm, 0.5–2 ft high. Flowering heads mostly or completely hidden in leaf sheaths; spikelets lance-shaped, tapering. IA, IL, IN, MI, (MN), OH, WI

Muhlenbergia mexicana Native. Jul–Oct. Common. Moist prairies & woods, banks, swamps, bogs. 30–90 cm, 1–3 ft high. Flowering heads nodding, often purplish; awns often present, 1–10 mm long. IA, IL, IN, MI, MN, OH, WI

Puffsheath dropseed

➔

Schizachyrium scoparium

➔

➔

Little bluestem

Mexican muhly, wirestem muhly

➔

FLOWERING HEADS BRANCHED Branches Narrow

Sporobolus neglectus Native. Aug–Oct. Infrequent to frequent. Dry prairies, riverbanks, sandy soils. 10–45 cm, 0.5–1.5 ft high. Flowering heads mostly or completely hidden in leaf sheaths; spikelets ovate, unawned. IA, IL, IN, MI, MN, OH, WI

FLOWERING HEADS NOT BRANCHED  ➔ Composite dropseed, rough dropseed Sporobolus compositus

Hidden dropseed

➔

see also panel above Native. Aug–Oct. More common south. Dry prairies, roadsides, cedar glades, partially disturbed semiopen sites. 40–130 cm, 1–4.5 ft high. Spikelets 4–6 mm long, rounded at tip. IA, IL, IN, (MI), (MN), OH, (WI)

Sporobolus clandestinus

Junegrass, prairie junegrass ➔

➔

Bristlegrasses, foxtails Setaria species

Koeleria macrantha

Exotic. Jun–Oct. Common, weedy. Disturbed sites, roadsides. 30–250 cm, 1–8 ft high. Flowering heads bristly, erect to nodding. IA, IL, IN, MI, MN, OH, WI

see also panel above Native. May–Aug. Frequent. Dry prairies, grassy woods, sandy soils. 20–130 cm, 0.5–4.5 ft high. Clumping; leaves relatively short & basal. IA, IL, IN, MI, MN, OH, WI

Timothy

➔

Native. Sep–Oct. Rare. Sand ridge prairies, roadsides. 40–130 cm, 1–4.5 ft high. Spikelets 4–10 mm long, narrower at tip. (IA), IL, IN, (MI), (WI)

Phleum pratense Exotic. Jun–Sep. Common. Moist prairies, pastures, disturbed sites. 50–150 cm, 1.5–5 ft high. Flowering heads densely cylindrical; spikelets U-shaped. IA, IL, IN, MI, MN, OH, WI

FLOWERING HEADS NOT BRANCHED  ➔ Canada wildrye Elymus canadensis Native. Jul–Sep. Common. Dry to wet prairies, dunes, banks, disturbed ground. 40–180 cm, 1–6 ft high. Flowering heads nodding; awns 10–50 mm long, curved. IA, IL, IN, MI, MN, OH, WI

Quackgrass, ➔ couchgrass Elymus repens Exotic. Jun–Sep. Common. Disturbed sites, dry soils. 50–100 cm, 1.5–3.5 ft high. Rhizomes well developed; leaves 6–10 mm wide, lax; awns absent or reduced (less than 4 mm long). IA, IL, IN, MI, MN, OH, WI

  ➔

Virginia wildrye

Elymus virginicus Native. Late Jun–Sep. Common. Forests, wet prairies. 30–130 cm, 1–4.5 ft high. Clumping; awns straight, 3–15 mm long (rarely more). IA, IL, IN, MI, MN, OH, WI

Western wheatgrass

➔

Pascopyrum smithii Native. Jun–Sep. Frequent. Dry prairies, moist alkaline clay, sandy soils. 20–100 cm, 0.5–3.5 ft high. Leaves 1–4.5 mm wide, stiff; awns typically absent, up to 5 mm long if present. IA, IL, IN, MI, MN, OH, WI

➔

Foxtail barley, squirreltail barley Hordeum jubatum Native. May–Sep. Common, weedy. Meadows, prairies, roadsides. 20–80 cm, 0.5–3 ft high. Tufted; awns 11–90 mm long. IA, IL, IN, MI, MN, OH, WI

THE GRASS PLANT

10 mm 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210

Most photographs, from the Grasses of Iowa website, www.eeob.iastate. edu/research/iowagrasses/index.html, are the work of Anna Gardner (1958– 2006). Additional photographs are by Lynn G. Clark, Deborah Lewis, Terry Lewis, and Gary Reiners. The drawings, by Elsie H. Froeschner (1913–2006), were originally published in The Grasses of Iowa by Richard W. Pohl. The illustration above was prepared by Katelyn McDonald.

FLOWERING HEADS BRANCHED Spikelets Plump, Branches More or Less Open Winter Rosettes Present, Leaves More or Less Broad  ➔ Hairy panicgrass Dichanthelium acuminatum Native. May–Sep. Common. Moist prairies, dry to wet open woods, bogs, swamps. 15–100 cm, 0.5–3.5 ft high. Ligule of hairs 1–5 mm long; spikelets 1–2 mm long, yellow-green to purple. (IA), IL, IN, MI, MN, OH, WI

Northern panicgrass

➔

Dichanthelium boreale Native. Jun–Aug. Rare to infrequent. Wet prairies or meadows, open woods, thickets. 18–75 cm, 0.5–2.5 ft high. Ligule of hairs 0.5 mm long; spikelets ca. 2 mm long, usually reddish. (IA), (IL), (IN), MI, MN, (OH), WI

 ➔ Leiberg’s panicgrass Dichanthelium leibergii Native. May–Aug. Frequent to common, rare east. Prairies, sandy woods. 24–80 cm, 0.75–3 ft high. Ligule a fringed membrane 0.3–0.5 mm long; spikelets 3.3–3.8 mm long, green to sometimes purple. IA, IL, (IN), (MI), MN, (OH), WI

Few-flowered ➔ panicgrass Dichanthelium oligosanthes Native. May–Sep. Common. Prairies, banks, dry woods. 20–75 cm, 0.5–2.5 ft high. Ligule of hairs 1–3 mm long; spikelets 2.7–4.2 mm long, green but often with orange or purple basal spot on one side. IA, IL, IN, MI, MN, OH, WI

 ➔ Stiff-leaved panicgrass Dichanthelium ovale Native. May–Jul. Infrequent to frequent. Drier sites, dunes, roadsides, sandy soils. 15–60 cm, 0.5–2 ft high. Ligule of hairs 1–5 mm long; spikelets 1.8–3 mm long, green to purple. IA, (IL), (IN), MI, MN, (OH), WI

FLOWERING HEADS BRANCHED Spikelets Plump, Branches More or Less Open Winter Rosettes Lacking, Leaves Narrow Starved panicgrass

➔

Dichanthelium depauperatum Native. May–Jun. Infrequent to frequent. Dry sandy woods, prairies, disturbed areas. 10–45 cm, 0.5–1.5 ft high. Lower leaves much smaller than upper; spikelets 3.2–4.3 mm long, 1–1.7 mm wide, beaked. IA, IL, (IN), MI, MN, (OH), WI

 ➔ Linear-leaved panicgrass Dichanthelium linearifolium Native. May–Jun. Infrequent to frequent. Dry or rocky prairies. 10–50 cm, 0.5–2 ft high. Lower leaves much smaller than upper; spikelets 2–3.2 mm long, 0.8–1.4 mm wide, acute, not beaked. IA, IL, IN, MI, MN, OH, WI

➔

Long-stalked panicgrass Dichanthelium perlongum

Native. Jun–Jul. Infrequent to frequent. Upland prairies. 10–50 cm, 0.5–2 ft high. Lower leaves much smaller than upper; spikelets 2.6–3.4 mm long, 1–1.7 mm wide, rounded, not beaked. IA, IL, (IN), MI, MN, (OH), WI

 ➔ Wilcox’s panicgrass Dichanthelium wilcoxianum Native. Jun–Jul. Infrequent. Upland prairies. 15–35 cm, 0.5–1 ft high. Lower & upper leaves more or less equal in size; spikelets 2.4–3.2 mm long, 0.7–1.2 mm wide, acute, not beaked. IA, IL, (IN), MN, WI

FLOWERING HEADS BRANCHED Branches Comblike  ➔ Sideoats grama Bouteloua curtipendula Native. Late Jun–Oct. Common. Dry prairies, grasslands. 8–80 cm, 0.5–3 ft high. Flowering heads long, branches short (ca. 1 cm long), falling off at maturity. IA, IL, (IN), (MI), MN, (OH), WI

Blue grama, ➔ eyelash grass Bouteloua gracilis Native. Late Jun–Sep. Rare east of IA & MN. Dry prairies, disturbed habitats. 20–70 cm, 0.5–2.5 ft high. Flowering head branches lack bristle at tip. IA, (IL), (MI), MN, (OH), (WI)

 ➔ Hairy grama Bouteloua hirsuta Native. Jul–Oct. Rare east of IL & WI. Dry prairies. 15–75 cm, 0.5–2.5 ft high. Flowering head branches have bristle at tip. IA, IL, MN, (OH), WI

Sloughgrass, ➔ prairie cordgrass Spartina pectinata Native. Late Jun–Oct. Common. Sloughs, marshes, prairie potholes. 100–250 cm, 3–8 ft high. Rhizomes well developed; leaf margins sharp. IA, IL, IN, MI, MN, OH, WI

Buffalograss ➔ Bouteloua dactyloides Native. Jun. Rare. Semiarid prairies, spreading along roadsides. 1–30 cm, to 1 ft high. Stolons well developed, forming mats; foliage grayish green. (IA), (IL), (MN), (WI)

FLOWERING HEADS BRANCHED Branches Fingerlike   Big bluestem, turkeyfoot ➔

Andropogon gerardii Native. Late Jul–Oct. Common. Moist to dry prairies, meadows. 100–300 cm, 3–10 ft high. Often bluish; flowering head branches somewhat hairy. IA, IL, IN, MI, MN, OH, WI

Sand bluestem ➔ Andropogon hallii Native. Aug. Rare. Sandhills, sandy soils. 40–200 cm, 1–7 ft high. Rhizomes well developed; flowering head branches very hairy. (IA), (IL), (MN)

 ➔ Eastern gamagrass Tripsacum dactyloides Native. Jun–Oct. Rare. Wetter areas, limestone outcrops. 100–200 cm, 3–7 ft high. Rhizomes short, knotty; basal part of flowering head branches beadlike. IA, IL, (IN), (MI), (OH)

Beadgrass, thin paspalum

➔

Paspalum setaceum Native. Jul–Sep. Infrequent to more frequent south. Sand prairies. 25–110 cm, 1–4 ft high. Spikelets all on one side of branches, round in outline, one side flat, one side convex. IA, IL, IN, (MI), (MN), OH, WI

FLOWERING HEADS BRANCHED Branches Variably Open, Awns Absent

➔

Switchgrass

➔

Bluejoint

Native. Jul–Oct. Common. Slopes, open woods, marshes, dry to moist sandy soils. 40–300 cm, 1–10 ft high. Rhizomes well developed but stems clumping. IA, IL, IN, MI, MN, OH, WI

Canada bluegrass

Kentucky bluegrass

➔

Panicum virgatum

see also 2d panel on right Native. Mid Jun–Sep. Frequent to common. Moist meadows, thickets, bog edges. 30–180 cm, 1–6 ft high. Rhizomes present; stems often branching above base; spikelets 2–4 mm long, grouped loosely. IA, IL, IN, MI, MN, OH, WI

➔

Calamagrostis canadensis

Poa compressa

Poa pratensis

Exotic. May–Sep. Common. Dry prairies, riparian areas, wet meadows, disturbed sites. 15–60 cm, 0.5–2 ft high. Rhizomes well developed; stems flattened; leaf tips boat-shaped. IA, IL, IN, MI, MN, OH, WI

Exotic. May–Jul. Common. Lawns, widely naturalized. 5–100 cm, up to 3.5 ft high. Rhizomes well developed; leaf tips boat-shaped; spikelets 2–3 mm long, clustered. IA, IL, IN, MI, MN, OH, WI

FLOWERING HEADS BRANCHED Branches Variably Open, Awns Absent Cluster fescue

➔

Festuca paradoxa Native. Jun–Jul. Rare. Prairies, open woods, thickets. 50–120 cm, 1.5–4 ft high. Spikelets clustered toward tips of drooping branches. IA, IL, (IN), (MN), (OH), WI

Fowl bluegrass

➔

Poa palustris Native. Late Jun–Sep. More common north. Drier woods & meadows to wet prairies. 15–120 cm, 0.5–4 ft high. Stolons frequently developed, stems in loose tufts; leaf tips boat-shaped; spikelets less than 2 mm long, clustered. IA, IL, IN, MI, MN, OH, WI

➔

Prairie dropseed

Sporobolus heterolepis Native. Aug–Oct. Common west of IL, otherwise rare. Dry prairies, edges of woods, roadsides, swamps, northfacing swales. 30–180 cm, 1–6 ft high. Leaves very narrow, lax; flowering heads scented. IA, IL, (IN), (MI), MN, (OH), WI

Sand dropseed

➔

Sporobolus cryptandrus Native. Jun–Sep. Common, rarer to east. Sand prairies, washes, rocky slopes, calcareous ridges. 30–100 cm, 1–3.5 ft high. Leaf sheaths hairy at their tops. IA, IL, (IN), MI, MN, (OH), WI

FLOWERING HEADS BRANCHED Branches Variably Open, Awns Short or Absent   Smooth brome ➔

Bromus inermis Exotic. Late May–Aug. Common, often aggressive. Disturbed sites. 50–130 cm, 1.5–4.5 ft high. Rhizomes well developed; leaf sheaths closed; flowering heads erect; awns usually absent. IA, IL, IN, MI, MN, OH, WI

Kalm’s brome, prairie brome

➔

Bromus kalmii Native. Jun–Aug. More common north. Moist prairies, sandy gravelly or limestone soils, open woods, calcareous fens. 50–100 cm, 1.5–3.5 ft high. Leaf sheaths closed, auricles absent; flowering heads nodding; awns 1.5–3 mm long. IA, IL, IN, MI, MN, OH, WI

Hairy woodbrome Bromus latiglumis ➔

Native. Aug–Sep. More common north. Wet woods & prairies, banks, alluvial plains. 80–150 cm, 2.5–5 ft high. Leaf sheaths closed, auricles present; flowering heads nodding; awns 3–4.5 mm long. IA, IL, IN, MI, MN, OH, WI

 ➔ Purpletop, purpletop tridens Tridens flavus

Bluejoint

➔

Native. Aug–Oct. Rare northwest of IL. Sandy soils, disturbed areas. 60–180 cm, 2–6 ft high. Leaf sheaths with margins overlapping; flowering heads erect, branches drooping; spikelets purplish, 5–10 mm long. (IA), IL, IN, (MI), (MN), OH, (WI)

Calamagrostis canadensis see also 2d panel on left Native. Mid Jun–Sep. Frequent to common. Moist meadows, thickets, bog edges. 30–180 cm, 1–6 ft high. Rhizomes present; stems often branching above base; spikelets 2–4 mm long, grouped loosely. IA, IL, IN, MI, MN, OH, WI

FLOWERING HEADS BRANCHED Branches Variably Open, Awns Present

Porcupine grass

➔

➔

Needle-and-thread

Native. May–Aug. Frequent to common. Dry prairies. 45–145 cm, 1.5–5 ft high. Spikelets 15–25 mm long, brown at maturity, base sharp; awns 90–190 mm long, twisted at base & bent twice above. IA, IL, (IN), MI, MN, (OH), WI

Green needlegrass

Indiangrass

➔

Hesperostipa spartea

Native. Jun–Jul. Rare. Dry prairies, cool grasslands. 12–110 cm, 0.5–4 ft high. Spikelets 7–14 mm long, usually light-colored at maturity, base sharp; awns 65–225 mm long, twisted at base & bent twice above. (IA), (IL), (IN), (MI), MN, (WI)

➔

Hesperostipa comata

Nassella viridula

Sorghastrum nutans

Native. May–Jul. Rare. Dry prairies, grasslands, open woods, sandy soils. 35–120 cm, 1–4 ft high. Spikelets plumper than in Hesperostipa, base blunt; awns 19–32 mm long. IA, (IL), MN, (WI)

Native. Late Jul–Oct. Common. Dry to moist prairies. 50–240 cm, 1.5–8 ft high. Flowering heads rusty red-brown; spikelets hairy, bases rounded; awns 10–22 mm long. IA, IL, IN, MI, MN, OH, WI

grasses in your pocket at the time of European settlement, tallgrass prairie was the iconic landscape in much of the Upper Midwest. Although its extent has been drastically reduced, intact prairie remnants exist, prairie species persist along roadsides, and interest in prairie reconstruction has increased. The basic prairie matrix is formed by grasses, yet their diversity and beauty are often underappreciated because their flowering structures are highly reduced to aid in wind pollination. This much-needed addition to Iowa’s popular series of laminated guides—the twentysixth in the series—illustrates fifty-five grass species characteristic of or commonly found on prairies of the Upper Midwest states of Illinois, Iowa, Indiana, Michigan, Minnesota, Ohio, and Wisconsin. For each species, its native or exotic status is followed by the months of flowering, abundance, general habitat, height, diagnostic features, geographic range, and, if relevant, threatened or endangered status.   Species are organized into groups by their most easily noted field characteristics. Are the flowering heads branched or unbranched? Are the branches dense, narrow, or fingerlike? Hold the grass you want to identify at arm’s length to establish its characteristics; then consult the main heading and subheading for each panel until you find the right combination. Note that some species occur in more than one group. Blooming time and height are typical ranges of variation. If a state is in parentheses, the species has a limited distribution there and may have threatened or endangered status. Although you can determine most features with your naked eye, a hand lens is invaluable for observing the finer details.

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